1. Field of the Invention
The present invention is related to moveable barriers that control, or direct, access by vehicles to a parking space where the vehicle drives in, and backs out. The invention is also suitable for moveable barriers that control, or direct, access by vehicles to parking areas or driveways where the vehicle drives through the moveable barrier if access is granted. More particularly, the invention addresses a mechanically-actuated barrier which can be controlled remotely and which is mounted directly to the roadbed.
2. Description of Prior Art
Electrically actuated gates, garage doors and similar barrier systems are now commonplace. There are numerous applications, however, where electrically powered barriers are not practically feasible. An example of such an application is the head of a driveway where no electricity is available. Another example is a parking spot in a multi-dwelling parking lot.
A battery-operated parking barrier is disclosed in U.S. Pat. No. 6,150,958 to Worsham. The apparatus works in a manner similar to remote-controlled garage door operators, with a barrier impeding access to a parking spot when the apparatus is set to block access. The barrier is actuated by an electric motor which powered by a rechargeable battery. The battery is charged by a solar panel. The Worsham system requires a complex mechanism, a heavy and expensive battery and a solar panel for charging that is ineffective in indoor applications.
A number of mechanically-actuated barriers have been previously disclosed. One system disclosed in U.S. Pat. No. 5,146,710 to Caldwell describes a mechanism for controlling access to a parking spot. Two pivoted plates are installed in the parking space, distanced from each other so that one plate can be engaged by the front wheel of the vehicle even as the barrier is in the blocking position. The second plate is installed so that it can only be accessed by the front wheel if the barrier is retracted, allowing full access to the parking space. The two plates are mechanically linked to create action akin to a see-saw, with one plate always protruding and one horizontal. The Caldwell barrier drops by its own weight when released by the driver to gain access to the parking space. As the car drives over the second plate, the weight of the wheel forces the plate to a horizontal position, and through a linkage, it forces the first plate (which is now behind the front wheels of the vehicle) to rise from its horizontal position. As the car pulls back to leave the parking space and the front wheel engages the first plate, the motion of the pivoting first plate is used to raise the barrier. The limitations of the Caldwell system lie in the complexity and cost of the product and its installation. The system comprises a number of separate assemblies that must be installed in the driveway, with mechanical linkages to interconnect them. In addition to the cost, such a method is likely to be unreliable when used in outdoor applications, subject to rust and debris. The Caldwell system also dictates that the barrier is always raised when the car leaves the spot. This may not be desirable, for example when the spot is to be left accessible for a visitor that may not have the key required to unlock the barrier. The Caldwell system is not suitable for drive-through applications, because once the vehicle passes over the retracted front plate, having the rear wheel engage the rear plate will force the barrier to extend into the blocking position while the vehicle is still over the barrier.
Another example of the prior art is U.S. Pat. No. 5,165,200 to Oga which describes a mechanically actuated parking space barrier where the motive force to displace the barrier is provided by pushing the barrier with the bumper of the car. The Oga system stores the energy to return the barrier to its frontal blocking position in a spring. Such an arrangement can store dangerous levels of potential energy, and hurt a person if the barrier is temporarily stuck in its retracted position after the car has departed. The system also requires mounting a rail or cable guide to keep the barrier on a track when it is being pushed back by the car. A further limitation of the system is the reluctance of drivers to push any item with the bumpers, and the likelihood of some car designs to cause marring of the car's grille by repeated engagement of the barrier.
The patent to Sayers, U.S. Pat. No. 5,299,882, discloses a gate that is mechanically operated. The gate is opened by a spring. The gate is closed by a depressible pedal that is actuated by the vehicle's weight. The Sayers system operates similarly to the Caldwell system, except that a spring provides the force to open the gate, whereas gravity is used to retract the barrier in the Caldwell invention. The Sayers system is applicable to gates that rotate on a vertical axis. It requires a considerable investment in the structure and construction of a gate, and is not suitable as a parking space barrier.
Moreover, in both the Sayers and Caldwell systems, the plate that is responsive to the weight of the car needs to be placed a significant distance away from the gate or barrier, as it closes the gate or barrier while the car weight is on the plate. Thus, the pedal must be positioned away from the gate or barrier a distance which exceeds the distance between the wheel of the vehicle and the vehicle's extremity (e.g., the front or rear bumper of the vehicle). Otherwise, when the wheel passes over the pedal and the gate or barrier is raised, the gate or barrier would hit the underside of the vehicle. For commercial vehicles (e.g., trash haulers, etc.), this distance may be in excess of twenty feet, making the Sayers or Caldwell systems impractical for these applications.
The patent to Trougouboff, U.S. Pat. No. 5,452,964, discloses a mechanical barrier with elastic spring to protect the barrier from accidental bumping by the car. The Trougouboff system does not offer remote control capability and requires manual release of the barrier.
U.S. Pat. No. 6,398,452 to Wagner et al. discloses a remote controlled barrier that is mechanically actuated. The device comprises a separate barrier and a separate pedal, both moveable around horizontal shafts but having different degrees of angular rotation allowed for each. The device has 3 states of operation: Disarmed, Armed and Blocking.
In the Disarmed state, the barrier is essentially horizontal and is locked in that position. The pedal is held in a slightly elevated state by a torsion spring. The device changes from the Disarmed state to an Armed state when a car drives over the pedal. The weight of the wheel against the pedal depresses the torsion spring and forces the pedal to an essentially horizontal position, where it is locked to the barrier.
In the Armed position, the pedal and the barrier are essentially horizontal, locked to each other and locked against movement in reference to the housing of the device. The device changes from the Armed state to the Blocking state when a command releases the latch that holds the barrier from rotating. The barrier and the pedal rotate to their respective raised positions, propelled by the torsion spring.
In the Blocking state, the barrier and the pedal are raised and locked against movement. The barrier, when in Blocking state, is raised through rotation to an essentially vertical position, to impeded the passage of a vehicle. The pedal is a metal flap that, when in the Blocking state, is raised somewhat from its resting horizontal position.
The Wagner system has a number of significant shortcomings. The design necessitates a side-by-side arrangement of the barrier and the pedal. This in turn means that the length of both the barrier and the pedal must be reduced as their sum total length is dictated by practical considerations of the total length of the device. The relatively short pedal therefore requires the driver to aim the wheel of the car to engage the pedal as the car is driven in (with the device in the Disarmed state). This is particularly demanding when the car is driven to a typical parking spot, where the car often needs to make a sharp turn to enter the spot from an access lane.
Another limitation of the Wagner system is its vulnerability to accidental or intentional abuse. Due to the narrow width of the pedal, the device must be installed close to the edge of the parking spot, so that the right front tire of the oncoming vehicle will engage the pedal as the car drives in when the device is in the Disarmed state. When in the Blocked state, the section of the device that is occupied by the pedal does not block relatively small vehicles from passing over the pedal, as long as the vehicle avoids the raised barrier next to the pedal. Furthermore, if a car attempts to park at an adjacent parking spot on the right and it overshoots its boundary, as is often the case when cars enter from a perpendicular narrow lane, one of the tires is likely to ride over the pedal. The locking mechanism associated with the pedal thus needs to withstand the full weight that rides on that tire, which is typically 1,000 lbs. Such repeated abuse is likely to either deform the pedal or damage the mechanism.
Yet another limitation of the Wagner system is that it requires a slot opening to the housing that contains the mechanism and its electronics. The parking device is installed on the pavement where it will be subjected to rain, standing water, salt and other environmentally hostile contaminants. Sealing a slot is practically cost prohibitive, presenting a serious issue of long term reliability of such a system.
In our co-pending application, Ser. No. 02/20626 filed Jun. 28, 2002, we disclose a remote controlled parking barrier which comprises a flag and a separate pedal. The flag acts as a signal post to indicate that the parking space is reserved and is not to be occupied by unauthorized drivers. Under remote command, a latch is released and the flag falls from its own weight to a horizontal position to allow access. In the process of the flag falling, the pedal is raised slightly. As the authorized car drives over the apparatus and over the pedal, the pedal is compressed and the energy is stored in a spring assembly. Both the pedal and the flag are locked in their respective positions. When a remote command is received, the flag lock is released and the stored energy in the spring is released to raise the flag back to its vertical, impede position.
The key shortcoming of said design (along with the fact that a separate pedal is used) is the mechanical limitations of the flag, preventing it from acting as a real threat to impede access. Due to the flag's long arm, the flag's weight translates to a significant torque requirement on the shaft of the flag. The torque required to raise the flag places a significant strain on the mechanical design, requiring heavy spring and a heavy mechanical construction. This raises the weight and cost of the unit significantly in direct relation to the weight of the flag. Practical considerations limit the weight of the flag to a light plastic tube. This in turn restricts the effectiveness of the flag to act as a barrier.
In view of the above limitations of the current art, all the above solutions have a limited commercial appeal.
It is one object of our invention to provide a remote controlled parking barrier that overcomes the shortcomings of the prior art.
It is another object of our invention to provide an economical and effective fully remote controlled barrier that can be mass produced, where the active mechanism can be manufactured as a single assembly that is relatively compact, can be attached to the surface of a roadway, can be used for both parking space access control and for drive-through access control, and that requires no external electrical power to operate.
Another object of the invention is to offer a solution to drive-through access control which works equally well regardless of the direction of the vehicle's approach to the barrier.